feat(backend): implement pricing engine for loyalty points and 3-level promotions

apps/backend/src/routes/orders.ts

@@ -22,7 +22,25 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
   .post("/", async ({ body, set }) => {
     try {
       const data = body as any;
-      
+      const settings = await prisma.storeSettings.findFirst()
+      const earnRate = settings?.pointsEarnRate || 1.0
+      const netAmount = data.totalAmount - data.shippingFee
+      const pointsEarned = Math.floor(Math.max(0, netAmount) * earnRate)
+
+      if (data.customerId && data.pointsUsed && data.pointsUsed > 0) {
+        // Verify customer has enough points
+        const customer = await prisma.customer.findUnique({ where: { id: data.customerId } })
+        if (!customer || customer.points < data.pointsUsed) {
+          set.status = 400
+          return { error: "Insufficient points" }
+        }
+        // Deduct points immediately
+        await prisma.customer.update({
+          where: { id: data.customerId },
+          data: { points: { decrement: data.pointsUsed } }
+        })
+      }
+
       const order = await prisma.order.create({
         data: {
           customerId: data.customerId,
@@ -30,10 +48,18 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
           customerEmail: data.customerEmail,
           customerPhone: data.customerPhone,
           shippingAddress: data.shippingAddress,
-          totalAmount: data.totalAmount,
-          shippingFee: data.shippingFee,
+          subtotal: data.subtotal || 0,
+          promoLevel1Name: data.promoLevel1Name,
+          promoLevel1Disc: data.promoLevel1Disc || 0,
+          promoLevel2Name: data.promoLevel2Name,
+          promoLevel2Disc: data.promoLevel2Disc || 0,
           couponCode: data.couponCode || null,
           discountAmount: data.discountAmount || 0,
+          pointsUsed: data.pointsUsed || 0,
+          pointsDiscount: data.pointsDiscount || 0,
+          pointsEarned: pointsEarned,
+          shippingFee: data.shippingFee,
+          totalAmount: data.totalAmount,
           items: {
             create: data.items.map((item: any) => ({
               productId: item.productId,
@@ -76,8 +102,15 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
       shippingAddress: t.String(),
       totalAmount: t.Number(),
       shippingFee: t.Number(),
+      subtotal: t.Optional(t.Number()),
+      promoLevel1Name: t.Optional(t.Nullable(t.String())),
+      promoLevel1Disc: t.Optional(t.Number()),
+      promoLevel2Name: t.Optional(t.Nullable(t.String())),
+      promoLevel2Disc: t.Optional(t.Number()),
       couponCode: t.Optional(t.Nullable(t.String())),
       discountAmount: t.Optional(t.Number()),
+      pointsUsed: t.Optional(t.Number()),
+      pointsDiscount: t.Optional(t.Number()),
       items: t.Array(t.Object({
         productId: t.Number(),
         variantId: t.Optional(t.Number()),
@@ -92,11 +125,31 @@ export const ordersRoute = new Elysia({ prefix: "/orders" })
   .patch("/:id/status", async ({ params: { id }, body, set }) => {
     try {
       const { status } = body as any;
-      return await prisma.order.update({
+      const order = await prisma.order.findUnique({ where: { id: Number(id) } });
+      
+      const updatedOrder = await prisma.order.update({
         where: { id: Number(id) },
         data: { status },
         include: { items: true }
       });
+
+      // Grant points if status becomes PAID and it wasn't PAID before
+      if (status === 'PAID' && order?.status !== 'PAID' && order?.customerId && order?.pointsEarned > 0) {
+        await prisma.customer.update({
+          where: { id: order.customerId },
+          data: { points: { increment: order.pointsEarned } }
+        });
+      }
+
+      // If status becomes CANCELLED, refund the points used
+      if (status === 'CANCELLED' && order?.status !== 'CANCELLED' && order?.customerId && order?.pointsUsed > 0) {
+        await prisma.customer.update({
+          where: { id: order.customerId },
+          data: { points: { increment: order.pointsUsed } }
+        });
+      }
+
+      return updatedOrder;
     } catch (err) {
       set.status = 500;
       return { error: "Failed to update order status" };